semantic

package
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 Go to latest Published: Feb 16, 2016 License: Apache-2.0 Imports: 14 Imported by: 0

Documentation

Overview

Package semantic contains the semantic analysis required to have a senantically valid parser. It includes the data conversion required to turn tokens into valid BadWolf structures. It also provides the hooks implementations required for buliding an actionable execution plan.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ToLiteral 

func ToLiteral(ce ConsumedElement) (*literal.Literal, error)

ToLiteral converts the node found by the lexer and converts it into a BadWolf literal.

func ToNode 

func ToNode(ce ConsumedElement) (*node.Node, error)

ToNode converts the node found by the lexer and converts it into a BadWolf node.

func ToPredicate 

func ToPredicate(ce ConsumedElement) (*predicate.Predicate, error)

ToPredicate converts the node found by the lexer and converts it into a BadWolf predicate.

Types

type AlwaysReturn 

type AlwaysReturn struct {
	V bool
}

AlwaysReturn evaluator always return the provided boolean value.

func (*AlwaysReturn) Evaluate 

func (a *AlwaysReturn) Evaluate(r table.Row) (bool, error)

Evaluate return the provided value.

type ClauseHook 

type ClauseHook func(*Statement, Symbol) (ClauseHook, error)

ClauseHook is a function hook for the parser that gets called on clause wide events.

func GroupByBindingsChecker 

func GroupByBindingsChecker() ClauseHook

GroupByBindingsChecker returns the singleton to check that the group by bindings are valid.

func HavingExpressionBuilder 

func HavingExpressionBuilder() ClauseHook

HavingExpressionBuilder returns the singleton to collect the tokens that form the having clause.

func OrderByBindingsChecker 

func OrderByBindingsChecker() ClauseHook

OrderByBindingsChecker returns the singleton to check that the group by bindings are valid.

func TypeBindingClauseHook 

func TypeBindingClauseHook(t StatementType) ClauseHook

TypeBindingClauseHook returns a ClauseHook that sets the binding type.

func VarBindingsGraphChecker 

func VarBindingsGraphChecker() ClauseHook

VarBindingsGraphChecker returns the singleton for checking a query statement for valid bidings in the select variables.

func WhereInitWorkingClauseHook 

func WhereInitWorkingClauseHook() ClauseHook

WhereInitWorkingClauseHook returns the singleton for graph accumulation.

func WhereNextWorkingClauseHook 

func WhereNextWorkingClauseHook() ClauseHook

WhereNextWorkingClauseHook returns the singleton for graph accumulation.

type ConsumedElement 

type ConsumedElement struct {
	// contains filtered or unexported fields
}

ConsumedElement groups the curernt element being processed by the parser.

func NewConsumedSymbol 

func NewConsumedSymbol(s Symbol) ConsumedElement

NewConsumedSymbol create a new consumed element that boxes a symbol.

func NewConsumedToken 

func NewConsumedToken(tkn *lexer.Token) ConsumedElement

NewConsumedToken create a new consumed element that boxes a roken.

func (ConsumedElement) IsSymbol 

func (c ConsumedElement) IsSymbol() bool

IsSymbol returns true if the boxed element is a symbol; false otherwise.

func (ConsumedElement) Symbol 

func (c ConsumedElement) Symbol() Symbol

Symbol returns the boxed symbol.

func (ConsumedElement) Token 

func (c ConsumedElement) Token() *lexer.Token

Token returns the boxed token.

type ElementHook 

type ElementHook func(*Statement, ConsumedElement) (ElementHook, error)

ElementHook is a function hook for the parser that gets called after an Element is confused.

func CollectGlobalBounds 

func CollectGlobalBounds() ElementHook

CollectGlobalBounds returns the global temporary bounds hook.

func DataAccumulatorHook 

func DataAccumulatorHook() ElementHook

DataAccumulatorHook returns the singleton for data accumulation.

func GraphAccumulatorHook 

func GraphAccumulatorHook() ElementHook

GraphAccumulatorHook returns the singleton for graph accumulation.

func GroupByBindings 

func GroupByBindings() ElementHook

GroupByBindings returns the singleton for collecting all the group by bidings.

func HavingExpression 

func HavingExpression() ElementHook

HavingExpression returns the singleton to collect the tokens that form the having clause.

func LimitCollection 

func LimitCollection() ElementHook

LimitCollection returns the limit collection hook.

func OrderByBindings 

func OrderByBindings() ElementHook

OrderByBindings returns the singleton for collecting all the group by bidings.

func VarAccumulatorHook 

func VarAccumulatorHook() ElementHook

VarAccumulatorHook returns the singleton for accumulating variable projections.

func WhereObjectClauseHook 

func WhereObjectClauseHook() ElementHook

WhereObjectClauseHook returns the singleton for working clause hooks that populates the object.

func WherePredicateClauseHook 

func WherePredicateClauseHook() ElementHook

WherePredicateClauseHook returns the singleton for working clause hooks that populates the predicate.

func WhereSubjectClauseHook 

func WhereSubjectClauseHook() ElementHook

WhereSubjectClauseHook returns the singleton for working clause hooks that populates the subject.

type Evaluator 

type Evaluator interface {
	// Evaluate computes the boolean value of the expression given a certain
	// restults table row. It will return an
	// error if it could not be evaluated for the provided table row.
	Evaluate(r table.Row) (bool, error)
}

Evaluator interface computes the evaluation of a boolean expression.

func NewBinaryBooleanExpression 

func NewBinaryBooleanExpression(op OP, lE, rE Evaluator) (Evaluator, error)

NewBinaryBooleanExpression creates a new binary boolean evalautor.

func NewEvaluationExpression 

func NewEvaluationExpression(op OP, lB, rB string) (Evaluator, error)

NewEvaluationExpression creates a new evaluator for two bindings in a row.

func NewEvaluator 

func NewEvaluator(ce []ConsumedElement) (Evaluator, error)

NewEvaluator construct an evaluator given a sequence of tokens. It will return a descriptive error if it could build it properly.

func NewUnaryBooleanExpression 

func NewUnaryBooleanExpression(op OP, lE Evaluator) (Evaluator, error)

NewUnaryBooleanExpression creates a new unary boolean evalautor.

type GraphClause 

type GraphClause struct {
	S          *node.Node
	SBinding   string
	SAlias     string
	STypeAlias string
	SIDAlias   string

	P                *predicate.Predicate
	PID              string
	PBinding         string
	PAlias           string
	PIDAlias         string
	PAnchorBinding   string
	PAnchorAlias     string
	PLowerBound      *time.Time
	PUpperBound      *time.Time
	PLowerBoundAlias string
	PUpperBoundAlias string
	PTemporal        bool

	O                *triple.Object
	OBinding         string
	OAlias           string
	OID              string
	OTypeAlias       string
	OIDAlias         string
	OAnchorBinding   string
	OAnchorAlias     string
	OLowerBound      *time.Time
	OUpperBound      *time.Time
	OLowerBoundAlias string
	OUpperBoundAlias string
	OTemporal        bool
}

GraphClause represents a clause of a graph pattern in a where clause.

func (*GraphClause) Bindings 

func (c *GraphClause) Bindings() []string

Bindings returns the list of unique bindings listed int he graph clause.

func (*GraphClause) BindingsMap 

func (c *GraphClause) BindingsMap() map[string]int

BindingsMap returns the binding map fo he graph clause.

func (*GraphClause) IsEmpty 

func (c *GraphClause) IsEmpty() bool

IsEmpty will return true if the are no set values in the clause.

func (*GraphClause) Specificity 

func (c *GraphClause) Specificity() int

Specificity return

type OP 

type OP int8

OP the operation to be use in the expression evaluation. 

const (
	// LT represents '<'
	LT OP = iota
	// GT represents '>”
	GT
	// EQ represents '=”
	EQ
	// NOT represents 'not'
	NOT
	// AND represents 'and'
	AND
	// OR represents 'or'
	OR
)

func (OP) String 

func (o OP) String() string

String returns a readable string of the operation.

type Projection 

type Projection struct {
	Binding  string
	Alias    string
	OP       lexer.TokenType // The information about what function to use.
	Modifier lexer.TokenType // The modifier for the selected op.
}

Projection contails the information required to project the outcome of querying with GraphClauses. It also contains the information of what aggregation function should be used.

func (*Projection) IsEmpty 

func (p *Projection) IsEmpty() bool

IsEmpty check if the given projection is empty.

func (*Projection) String 

func (p *Projection) String() string

String returns a readable form of the projection.

type Statement 

type Statement struct {
	// contains filtered or unexported fields
}

Statement contains all the semantic information extract from the parsing

func (*Statement) AddData 

func (s *Statement) AddData(d *triple.Triple)

AddData adds a triple to a given statement's data.

func (*Statement) AddGraph 

func (s *Statement) AddGraph(g string)

AddGraph adds a graph to a given https://critique.corp.google.com/#review/101398527statement.

func (*Statement) AddWorkingGrpahClause 

func (s *Statement) AddWorkingGrpahClause()

AddWorkingGrpahClause add the current working graph clause to the set of clauses that form the graph pattern.

func (*Statement) AddWorkingProjection 

func (s *Statement) AddWorkingProjection()

AddWorkingProjection add the current projection variableto the set of projects that this statement.

func (*Statement) BindType 

func (s *Statement) BindType(st StatementType)

BindType set he type of a statement.

func (*Statement) Bindings 

func (s *Statement) Bindings() []string

Bindings retuns the list of bindings available on the graph clauses for he statement.

func (*Statement) BindingsMap 

func (s *Statement) BindingsMap() map[string]int

BindingsMap retuns the set of bindings available on the graph clauses for he statement.

func (*Statement) Data 

func (s *Statement) Data() []*triple.Triple

Data returns the data available for the given statement.

func (*Statement) GlobalLookupOptions 

func (s *Statement) GlobalLookupOptions() *storage.LookupOptions

GlobalLookupOptions returns the global lookup options available in the statement.

func (*Statement) GraphPatternClauses 

func (s *Statement) GraphPatternClauses() []*GraphClause

GraphPatternClauses return the list of graph pattern clauses

func (*Statement) Graphs 

func (s *Statement) Graphs() []string

Graphs returns the list of graphs listed on the statement.

func (*Statement) GroupByBindings 

func (s *Statement) GroupByBindings() []string

GroupByBindings returns the bindings used on the group by statement.

func (*Statement) HasHavingClause 

func (s *Statement) HasHavingClause() bool

HasHavingClause returns true if there is a having clause.

func (*Statement) HavingEvaluator 

func (s *Statement) HavingEvaluator() Evaluator

HavingEvaluator returns the evaluator constructed for the provided having clause.

func (*Statement) InputBindings 

func (s *Statement) InputBindings() []string

InputBindings returns the list of incomming binding feed from a where clause.

func (*Statement) IsLimitSet 

func (s *Statement) IsLimitSet() bool

IsLimitSet returns true if the limit is set.

func (*Statement) Limit 

func (s *Statement) Limit() int64

Limit returns the limit value set in the limit clause.

func (*Statement) OrderByConfig 

func (s *Statement) OrderByConfig() table.SortConfig

OrderByConfig returns the sort configuration specified by the order by statement.

func (*Statement) OutputBindings 

func (s *Statement) OutputBindings() []string

OutputBindings returns the list of binding that a query will return.

func (*Statement) Projections 

func (s *Statement) Projections() []*Projection

Projections returns all the available projections.

func (*Statement) ResetProjection 

func (s *Statement) ResetProjection()

ResetProjection resets the current working variable projection.

func (*Statement) ResetWorkingGraphClause 

func (s *Statement) ResetWorkingGraphClause()

ResetWorkingGraphClause resets the current working graph clause.

func (*Statement) SortedGraphPatternClauses 

func (s *Statement) SortedGraphPatternClauses() []*GraphClause

SortedGraphPatternClauses return the list of graph pattern clauses

func (*Statement) Type 

func (s *Statement) Type() StatementType

Type returns the type of the statement.

func (*Statement) WorkingClause 

func (s *Statement) WorkingClause() *GraphClause

WorkingClause returns the current working clause.

func (*Statement) WorkingProjection 

func (s *Statement) WorkingProjection() *Projection

WorkingProjection returns the current working variable projection.

type StatementType 

type StatementType int8

StatementType describes the type of statement being represented. 

const (
	// Query statement.
	Query StatementType = iota
	// Insert statemrnt.
	Insert
	// Delete statement.
	Delete
	// Create statement.
	Create
	// Drop statement.
	Drop
)

func (StatementType) String 

func (t StatementType) String() string

String provides a readable version of the StatementType.

type Symbol 

type Symbol string

Symbol of the LLk left factored grammar.

func (Symbol) String 

func (s Symbol) String() string

String returns a string representation of the symbol

Source Files

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